Bottled water’s energy budget
In a short research paper, two staff members from the Pacific Institute examine how energy is used in the production and distribution of bottled water. Bottle production and transportation are by far the largest energy users, with pre-bottling water processing (filtration and disinfection), filling and sealing the bottles, and chilling the water requiring minimal amounts of energy. Although the energy needed to manufacture a one liter plastic bottle is relatively independent of the water's source (about 4 megajoules for a one liter bottle), transportation of the water from source to market is where big differences can appear. Consequently, the authors considered three sources of bottled water for the Los Angeles area: 1) municipal water, bottled locally, 2) spring water bottled in the South Pacific, and 3) spring water bottled in France. Transporting the local water to market requires 1.6 megajoules per liter, transporting the water from the South Pacific water requires 4 megajoules per liter and shipping bottles water from France water requires 5.6 megajoules per liter. In total, the range of energy inputs for these three cases ranges from 5.6 to 10.6 megajoules per liter of bottled water. For reference, the authors report that it takes only 0.005 megajoules to treat and distribute a liter of tap water through municipal water systems. (Environmental Research Letters)
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